import java.util.Random;

public class Solution2 {
    public int[] sortArray(int[] nums) {
        qsort(nums, 0, nums.length - 1);
        return nums;
    }

    public void qsort(int[] nums, int l, int r) {
        if(l >= r) {
            return;
        }

        // 数组分三块
        int key = nums[new Random().nextInt(r - l + 1) + l];
        int left = l - 1;
        int right = r + 1;
        int i = l;
        while(i < right) {
            if(nums[i] < key) {
                swap(nums, ++left, i++);
            }else if(nums[i] == key) {
                i++;
            }else {
                swap(nums, --right, i);
            }
        }

        qsort(nums, l, left);
        qsort(nums, right, r);
    }

    public void swap(int[] nums, int i, int j) {
        int temp = nums[i];
        nums[i] = nums[j];
        nums[j] = temp;
    }
}
